When it comes to dark money groups, what really separates Crossroads GPS from its liberal counterparts is tens of millions of dollars in FEC-reported political spending, writes Robert Maguire of the Center for Responsive Politics.

-by Robert Maguire

June 2, 2013- Karl Rove, the co-founder of Crossroads GPS, has taken of late to asking why his 501(c)(4) social welfare group has been scrutinized, while “liberal groups have operated for decades in the same way GPS does without Democrats complaining.” He singled out the League of Conservation Voters, NARAL Pro-Choice America, unions and the NAACP.

The group Rove helped found has massively outspent other 501(c)(4)s on political expenditures in the last two national election cycles, while fielding a tiny staff and offering no discernible social welfare purpose.

If Rove and his colleagues intend to make the point that there are liberal groups that emulate the scheme perfected by Crossroads GPS, they are absolutely correct. Priorities USA, a 501(c)(4) organization started by former Obama aides, raised $2.3 million from only 5 donors according to its only tax returns filed to date. Like Crossroads GPS and every other 501(c)(4), Priorities USA doesn’t have to tell us who those donors were. Both groups also have a separate, disclosing super PAC—which, for the sake of clarity, do not factor into the data discussed in this article.

While 501(c)(4) organizations are supposed to have social welfare as their primary purpose, it’s often hard to tell how they provide for the “common good and general welfare of the people” as the IRS describes it. Priorities USA spent hundreds of thousands on media consultants and television ads that don’t appear to have ever run on air. They also gave a grant to another liberal 501(c)(4), American Bridge 21st Century Foundation, which appears to do little more than provide opposition research to liberal and progressive groups making ads in races across the country.